1. Field of the Invention
The present invention is related to a method of controlling network resources and/or connection parameters of a communication connection in a communication network, and/or to a corresponding system and/or a corresponding network control element. The following specification is in particular directed to an indication of a service flow termination, for example, in a packet based communication network.
2. Description of the Related Prior Art
In the last years, an increasingly extension of communication networks, such as wire based communication networks like the Integrated Services Digital Network (ISDN), or wireless communication networks like cdma2000 (code division multiple access) system, cellular 3rd generation communication networks like the Universal Mobile Telecommunications System (UMTS), the General Packet Radio System (GPRS), or other wireless communication system, such as the Wireless Local Area Network (WLAN), took place all over the world. Various organizations, for example the 3rd Generation Partnership Project (3GPP), the International Telecommunication Union (ITU), 3rd Generation Partnership Project 2 (3GPP2), Internet Engineering Task Force (IETF), and the like, are working on standards for telecommunication network and multiple access environments.
In general, the system structure of a communication network is such that a subscriber's user equipment, such as a mobile station, a mobile phone, a fixed phone, a personal computer (PC), a laptop, a personal digital assistant (PDA) or the like, is connected via respective transceivers and interfaces, such as an air interface, a wired interface or the like, to an access network subsystem. The access network subsystem controls the communication connection to and from the user equipment and is connected via an interface to a corresponding core or backbone network subsystem. The core (or backbone) network subsystem switches the data transmitted via the communication connection to a destination, such as another user equipment, a service provider (server/proxy), or another communication network. It is to be noted that the core network subsystem may be connected to a plurality of access network subsystems. Depending on the used communication network, the actual network structure may vary, as known for those skilled in the art and defined in respective specifications, for example, for UMTS, GSM and the like.
Generally, “connections” may be discriminated into various types. For example, one type of connection is a connection between a user equipment and another user equipment/database/server/etc. Another type of connection is between the user equipment and e.g. a GGSN (Gateway GPRS Support Node) of a GPRS (General Packet Radio Services) system. In both cases the user equipment is involved but the respective terminating endpoint of the connection is different. Basically, for properly establishing and handling a connection between network elements such as the user equipment and another user equipment, a database, a server, etc., one or more intermediate network elements such as connection control nodes, support nodes and/or service nodes can be involved. One or more connection parameters are used for defining connection characteristics. This includes, for example, in case of the establishment of a packet based data transmission protocol, such as a PDP (Packet Data Protocol) context, the definition of information about quality of service (QoS) requested or provided (such as a traffic class, an allocation/retention priority, a traffic handling priority, a guaranteed bitrate, a maximum bitrate and the like), charging-related information, such as a charging class, etc.
Furthermore, it is possible to establish, via a communication connection, different types of services for the user. Data to be transmitted in connection with these services are sent, for example, by packets in service flows from one network element to another. As an example for these services, non real-time services and real-time services, such as email, downloading, browsing, streaming, IP multimedia services and the like can be named.
In particular in cases where a communication connection involves two or more networks of different types such as networks using different transmission protocols, e.g. GPRS/UMTS-based networks and IP-based networks, problems may occur in properly establishing the communication connection and setting the communication connection parameters such that they are optimal for the service in question.
Hitherto, there have been proposed several concepts for achieving a solution therefor. For example, in the case of a 3GPP based network, such as UMTS/GPRS, the following solutions are proposed.
Generally, communication connection parameters and resources, such as a QoS authorization, may be requested for a communication connection, e.g. with regard to a respective PDP context activation and/or modification. Furthermore, there are also proposals to request respective parameters and resources for separate service flows using the communication connection. These parameters and resources for separate service flows may be different to those originally requested and provided for the PDP context, for example.
While in a standard 3GPP system QoS is defined per Access Point Name (APN), in 3GPP Release 5 (see, for example, 3GPP specification TS 23.207, ver5.7.9 (2003-03)), a so-called Policy Decision Function (PDF) is introduced for dynamically authorizing of QoS for services provided by the IP Multimedia Subsystem (IMS). IMS specific information, Authorization Token and Flow ID(s) are used as binding information when requesting QoS authorization for a PDP context. According to 3GPP Release 5, the PDF (or also Policy Control Function PCF) is described to be implemented together with a Proxy Connection State Control Function (P-CSCF) of the IMS.
Regarding the basic communication between a GGSN (Gateway GPRS Support node) and a PDF, reference can also be made to the International patent application No. WO 02/32165 of the applicant.
In 3GPP Release 6 (see, for example, 3GPP specification TR 23.917, ver0.7.1 (2003-02)), it is planned to extend the dynamic QoS authorization to include also other services than those provided by the IMS, e.g. streaming services (for example, Packet Switched Streaming Services (PSS)). Furthermore, according to the current understanding of 3GGP Release 6, a stand-alone Policy Decision Function (PDF) with standardized interfaces towards both the GGSN (the so-called Go-interface) and the Application Function, e.g. IMS/PSS server/proxy (the so-called Gq-interface) are planned.
Thus, it is to be noted that in 3GPP Release 5 and 3GPP Release 6 solutions, a dynamic QoS control for a communication connection is possible for session-based services, and in particular real-time services such as Voice over IP (VoIP). More generally, PSS streaming service is planned to be added to dynamically authorized services in 3GPP Release 6, in addition to IMS services of 3GPP Release 5.
Another approach for enhancing QoS support for IP services is the usage of so-called service aware core network element, such as a service aware GGSN (saGGSN), or the usage of so-called Intelligent Service Nodes (ISN). The saGGSN and the ISN are service aware products which can provide, for example, specific charging functions. A GGSN provides charging per PDP context whereas service specific charging functions, as one example, can operate on a service flow level. The saGGSN and the ISN are currently under definition. A saGGSN allows for the detection of the QoS level at the network edge for selected services. With these enhanced core network elements, QoS can be controlled on a communication connection (e.g. PDP context) basis, or on a service access point (sAP) basis, or on a service basis within a sAP, or on a service flow basis within a service.
When a communication connection is terminated, usually, the resources allocated to the communication connection are to be released in the network. Conventionally, in a case where the communication connection is established by a PDP context, such a release process is commonly known to persons skilled in the art. On the other hand, when for example a PDF is involved for authorizing service flows for a communication connection using a PDP context, the following procedure is implemented. When the PDP context is to be released, the network control element, such as the GGSN, sends a corresponding indication to the PDF. Otherwise, the user equipment only can terminate specific service flow(s) in a PDP context. When the GGSN receives a corresponding release instruction from the user equipment, it sends a new request with a further set of binding information to the corresponding PDF. This binding information does not comprise the binding for the service(s) flow being terminated. Then, the (new) service flows being requested by the new set of binding information are processed (authorized) by the PDF accordingly.
However, present existing terminals usually do not support simultaneous PDP contexts, but only one PDP context can be supported. Thus, when there is a need to use several types of services at the same time, all the service flows have to be carried inside the same PDP context. However, when several service flows are carried inside one PDP context, there are no effective methods for network control elements/entities or nodes such as the GGSN, for example, to detect the termination of one service flow, to control PDP context parameters, such as QoS parameters, and to modify the PDP context parameters back to the earlier values after termination of one service flow.